Ventilated rotary-hook mechanism



R. K. HOHMANN ET AL VENTILATED ROTARY HOOK MECHANISM Fil ed Sept. 22;1924.

u A I 10 IINVENTORS K 0&1 Z

- ATTORNEY Patented Aug. 17, 1926.

. STATES PATENT. OFFICE.

RICHARD K. HOHMANN, OF PERU, INDIANA, AND DAVID BESWICK, 0F BROOKLYN,NEW YORK; SAID I-IOHMANN ASSIGNOR OF HIS ENTIRE RIGHT TO HOHMANN SEWING-MACHINE COIMPANY, 0F PERU, INDIANA, A CORPORATION OF INDIANA, AND SAIDIBESWIGK ASSIGNOR OF HIS ENTIRE RIGHT TO FREDERICK OSANN COM- PANY, OFNEW YORK, N. Y., A CORPORATION OF NEW YORK.

VENTILATED ROTARY-HOOK MECHANISM.

Application filed September 22, 1924. Serial No. 739,022.

The object of the present invention is to mechative provisions wherebyit acts as a fan to draw air over its surfaces and those of the carrierto thereby absorb and dissipate the frictional heat developed inoperation. Advantageously also, the carrier or bobbin housing is formedwith a special ventilating passage. The invention is of particularutility in connection with the high speed big bobbin machines heretoforedeveloped by one of us, to-wit: Richard K. Hohmann, on account of thevery high peripheral speed of the surfaces of the hook running incontact with the carrier surfaces.

The various features of novelty which characterize our invention arepointed out with particularity in the claims annexed to and forming apart of this specification; but for a better understandin of theinvention, its advantages and speci c objects attained with, it,reference should, be had to the accompanying drawing and descriptivematter inwhich we have illustrated and described a preferred embodimentof the invention.

Of the drawings:

Fig. 1' is afront elevation of the rotary stitch forming mechanism of arotary hook sewing machine;

Fig. 2 is a section on the line 22 of.

Fig. 1;

Fig. 3 is a section on the line 3-3 of Fig. 2; Fig. 4 is a perspectiveview of a portion of the rotary hook member; and

Fig. *5 is'an elevation of another POT. tion of the rotary hook member.I

The rotary hook member A illustrated in the drawings-comprises a hubportion adapted to be secured on the end of the hook shaft (.not shown),and spoke arms A 'integrally connecting the hub toa cylindrical rimportion A A second hook rim part A has a portion fitting overthe rimpart A and is secured to the latter as by means of screws B tapped intothe rim part A and passing through holes A in the rim part A. The rimpart A is provided with an internal rojecting rib or flange A atits'front end forming the front wall of a circumferential bearing grooveC, the rear wall of which is formed by the front edge of the rim portionA and the outer wall of which is formed by the body of the rim part A.The rim portion of the hook member is notched to form a loop engagingbeak A", and the beak forming notch is spanned by the usual deflectorstrip D.

- The bearing groove C in the hook member receives the bearing rim E ofthe nonrotating thread carrier or bobbin housing E. The latter is shownas having the usual provisions E forholding the thread carrier againstrotation with the hook member, and is notched to provide the usualthread engaging hook E and opposing shoulder E The bobbin housing isprovided with a central post E on which is normally secured the sleeveportion F of a separable bobbin housing part F which is latched in placeon the end of the post E by a latch member G. H represents a threadbobbin journalled on the sleeve F.

The rotary hook member and bobbin housing, in so' far as they have beendescribed above, embody no feature of the present invention, but on thecontrary are of the type previo usly developed by Richard K. Hohmann foruse in 'a high speed big ,bobbin machine with which the presentinvention may be'employed with-especial advantage because of the highperipheral speed of the hook member. In such a machine the diameter ofthe thread housing bearing rim may well be an inch and a half orso, andthe hook member may make eight or nine thousand revolutions er minute.With such relative speed of t e contacting surfaces of lubricated. Theheating up of the contacting surfaces is objectionable as it increasesthe frictional wear, and is further objectionable because it makes thebobbin housing part F too hot for comfortable handling by the operatorin effecting bobbin replacements. I

To avoid this heating up of the parts, we have provided the mechanismshown with simple and effective ventilating provisions which co-operateto create an-air fiow over the surfaces of, the hook member and housingeffectually cooling these parts." These provisions, in the preferredconstruction illustrated, comprise fan blades I secured to the spiderarms AT of the hook member A. These blades may be strai ht or curved, asshown, to correspond to t e contour of the front edges of the arms A andextcnd outward a short distance beyond the periphery of the rim portionA and extend rearward some distance beyond the arms A. A disc K at therear of the blades fits snugly about the hub portion of the hook member,and is secured against the rear edges of the fan blades I by rivets M bywhich the disc K is secured to the arms A. L represents spacing Washerssurrounding the rivets M. With this arrangement the disc K forms therear wall of the fan chamber of a centrifugal fan. The blades I draw airinto this fan chamber from the space surrounded by the rim of the hookmember A, and this air is discharged at the periphery of the fanchamber.

In addition to the ventilating provisions formed by the fan blades I andassociated parts, we advantageously form ports or channels A through theportion of the rim of the hook member A forming the outer wall of thebearing groove C. The walls of the ports A 9 serve as fan vanes tocreate a flow of air through the bearing groove. The fan action thusprovided for might be a centrlfugal' fan action, but advantageously asshown, the ports are forwardly inclined to obtain an lmpulse fan actionwhereby air is drawn into the outer ends of the ports A and is deliveredat the inner ends of the ports into the bearing groove 0. To augment theimpulse fan action, the outer ends of the ports A are enlarged as bycounters1nk1ng, the enlargements A 'being mainly at the forward sides ofthe axes of the ports A. To furtherthe fan action of the channels orports A, we advantageously form a peripheral groove E in the bearing rimE of the bobbin housing .member E. The groove E may well be open at itsend adjacent the shoulder E, but will ordinarily be closed at its otherend. The groove 6 is open to the interior of the hook chamber throughthe usual thread clearing slots E formed in the bearing rim.

With the simple and effective provisions described air is drawn into thehook member through the ports A into immediate contact with the engagingsurfaces of the hook member and bobbin housing. The air circulation thusobtained, is augmented by the action of the fan blades I which continu-.

ation, while without such provisions a, few

minutes operation of the mechanism will heat the bobbin housing so hotasto make it practically impossible for the operator to handle it withbare hands.

While in accordance with the provisions of the statuteswe haveillustrated and ,described the best form of our invention now known tous, it will be apparent to those skilled in the art that changes in theform of apparatus specifically illustrated and. de-

scribed herein may be made without departing from the spirit of ourinvention as set forth in the appended claims, and that certain featuresof our invention may sometimes be employedwith advantage without acorreslponding use of other features. I

aving now described our invention what we claim as new and desire tosecure by Letters Patent is: 1. In a rotary hook sewing machine mechanism comprisin a rotating hook member having a bobbin ousing chamberand a 'nonrotating bobbin housing mounted in said chamber, theimprovement which consists in provisions creatmg a fan action drawingair through said chamber and comprising a fan chamber at the rear of thefirst mentioned chamber receiving air from the latter and discharging itat the periphery of the fan chamber.

2. In a rotary hook sewing machine mechanism comprising a rotating hookmember having an internal bearing groove and a non-rotating bobbinhousing journalled in said groove, the improvement which consists inprovisions for creating a fan action forcing air through said groovecomprising ports through the peripheral wall of the bearing groove. 1

3. In a rotaryhook sewing machine mechanism comprising a rotating hook\member having an internal bearing groove and a non-rotating'bobbinhousing journalled in said groove, the improvement which consists inprovisions for creating a fan action forcing air through said groovecomprising forwardly inclined ports through the peripheral wall of thebearing groove.

4. In a rotary hook sewing machine mechanism comprising a rotating hookmember having an internal bearing groove with ports in the peripheralwall of the groove, and a non-rotating bobbin housing having a bearingrib mounted in said groove and formed with a periphreal channel.

5. In a rotary hook sewing machine mechanism comprising a rotating hookmember having an internal bearing groove and a non-rotating bobbinhousing mounted therein, the improvement which consists in for wardlyinclined ports extending through the peripheral wall of said bearinggroove, and

provisions incorporated in the hook member for creating a fan actiondrawing air out of w the hook at the rear of the latter.

6. A rotary hook member for a rotary hook sewing machine comprising huband rim portions and arms connecting said portions, fan blade portsextending 'rearwardly 20 Kings and State of New York, this 19th day 25of September, A. D. 1924.

RICHARD K. HOHMANN. DAVID BESWICK.

